This happens a lot at HLE's that don't have on site gas. They need to get cars out so they issue and mark the fuel level on the contract. While I think cars should be full when I receive them, if I'm only expected to return it at the level I receive it at I only return it at that level. That's my job in the contract as a renter. I don't know if or where it says a car needs to be given out at a Full tank. That's common sense and good business sense towards the customer service side of things but isn't required as far as I know. I just consider "full" to be the gas level I receive the vehicle at.